Earth is threatened by a malevolent species of sentient robots. You also need a refill of toilet paper and some cucumber-mint-scented hand sanitizer, and you need them fast. Who are you going to call? Amazon Prime, defender of both our planet and two-day shipping.

Caron Arnold, creative director of Fusion Marketing in St. Louis, conquered the office Halloween costume contest with a clever and beautifully built costume that combines Optimus Prime from "Transformers" with Amazon Prime's fast shipping service.

Arnold says it took her about 10 hours over the course of several days to compile a collection of cardboard boxes, complete with Amazon tape advertising the Echo voice assistant, into a wearable costume that looks like Optimus Prime in bipedal form (his other incarnation is as a semi truck).

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Arnold doesn't work for Amazon and the online retailing behemoth isn't one of her firm's clients. She does, however, make extensive use of Prime. She collected her Prime boxes, and co-workers contributed their own containers to the cause.

The clothing under the costume is a perfect match for the color scheme. Arnold, a Star Wars fan, says the leggings have a C-3PO design, while the turtleneck and gloves came from Amazon. The crowning glory of the outfit is the tape gun that replaces Optimus Prime's usual weapon, an ion blaster.

Arnold prefers the old-school "Transformers" animated television series to the new blockbuster movies. Her general fondness for robots (Data from Star Trek and R2-D2 from Star Wars are favorites) made the costume a perfect fit for her. And, yes, she took first place in the contest.